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20 H. M. Baranowska, R. Rezler

contribution reveals a transition from the ordered helical fragments of the polymer chains to the State of spatially disordered coil. Some of the water molecules penetrating into the swelling starch grains become immobile and bound to the starch hydroxyl groups unshielded in the process of gelation. Simultaneously, the crystal phase melts and the concentration of the active segments of the amorphous lattice decreases with increase in temperaturę, causing a deshielding of morę hydrophilic group. They bound morę water molecules limiting their dynamics. This influences the temperaturę de-pendence ofTi relaxation time (Fig. 1).

The spatial lattice of macromolecular gel starts forming under conditions when stable bonds can form among fragments of different macromolecules. This process occurs on cooling of hot starch gels of sufficient both concentration and degree of ho-mogeneity. The intermolecular bonds form as a result of coiling of neighbouring fragments of the macromolecule chains taking place on decreasing temperaturę, and their association to bihelical forms, characteristic of native and retrograded starch. In order to determine the effect of the temperaturę of gelation on the finał structure of the mac-romolccular gel, the relaxation time was measured for starch Systems gelled at +70°C and +100°C. The measurements were performed at +20°C at 24 hours after the comple-tion of gelation. The T] relaxation time values obtained were within the error limit (±5%) for both systcms (Tablc 1). This result leads to a conclusion that in spite of different temperatures of gelation, the spatial lattices formed as a result of the retrograda-tion processes are similar and temperaturę of +70°C is sufficient for starch gelation within the concentration rangę studied.

For the starch-protein Systems two different courses of temperaturę dependencies of T] relaxation time were observed. For the Systems of starch-to-protein concentra-tions ratio of 9:1, 8:2 and 7:3, the value ofT| relaxation time increased with increase in temperaturę. This dependence was interpreted as follows. The water molecules initially bound with the protein are released as a result of the protein denaturation process above +50°C [5, 9], At the same time, because of the uncoiling of the starch molecules, the water molecules take part in the formation of the lattice. In generał, these two processes evoked no macroscopic change in the water molecules dynamics. The situa-tion is different for the systems containing starch and protein at the concentration ratio of 6:4 and 5:5, for which the temperaturę dependencies of T, relaxation time revealed maxima and minima in the temperaturę rangę studied. At the beginning, the Ti value increases with temperaturę increasing up to +55°C, which suggested the release of water molecules as a result of protein denaturation and an increase in their mobility. A significant decrease in Ti observed at +60°C for the system of the ratio of 6:4 and at +65°C for the system of the ratio of 5:5, was probably related to the uncoiling of starch chains as well as participation of water molecules in the lattice formation and bonding of some of the water molecules at the hydrophilous sites of the peptide chains de-